It's C++, but UB allows the compiler to call a function the programmer never called
https://kristerw.blogspot.com/2017/09/why-undefined-behavior...
I'm not sure how any compiler writer can condone this behaviour.
https://kristerw.blogspot.com/2017/09/why-undefined-behavior...
I'm not sure how any compiler writer can condone this behaviour.
1. Determine possible function call targets
2. Eliminate invalid targets from call set
3. If only one target remains, replace indirect call with direct call
That might be useful for something like devirtualization, but also could lead to the behavior exhibited in that blog post.
Indeed, the second blog post [0] shows that if there are two possible call targets, LLVM could generate an indirect call like what you may expect.
[0]: https://kristerw.blogspot.com/2017/09/follow-up-on-why-undef...
The NeverCalled function has external visibility so it could be eventually called by another CU, and it definitely references (or takes the address of) the supposedly unused "EraseAll" function. In order to be a legal program, some other CU has to call the NeverCalled at some point before main(), and the compiler is just assuming that.